“Assistance of counsel”是美国宪法第六修正案赋予被告在刑事诉讼中的一项权利，原文是“In all criminal prosecutions, the accused shall enjoy the right...to have the Assistance of Counsel for his defence.”中文就是，在刑事诉讼中，被告有权获得律师协助为其辩护。这项权利要求被告必须由聘请的律师或法庭指定的律师提供协助和代理，由律师制定辩护策略，不受政府干预，这样有助于个人和政府处于对抗地位的刑事司法系统实现公平正义。这里的协助应该是有效协助（effective assistance of counsel），就是律师为被告人提供了认真而有意义的法律服务，包括告知了被告人他所享有的权利；诚实、精通法律且有能力的律师被给予了合理的机会去履行他所承担的义务。但是，如果律师未向被告提供足够的法律协助，可视为无效协助（ineffective assistance of counsel）。若被告为了推翻判决或死刑判决而声称律师提供的协助无效，则需要作出以下证明：第一，律师提供的协助不合理，因而无效；第二，如果律师未出错，那么诉讼程序可能会产生不同的结果。

例句1：

原文：

With respect to a claim of ineffective assistance of counsel, an appellant bears the burden of demonstrating that (a) defense counsel’s performance was deficient, and (b) this deficient performance was prejudicial; and this applies in the context of cases involving guilty pleas; however, the prejudice inquiry is modified to focus on whether the ineffective performance affected the outcome of the plea process; that is, the appellant must establish prejudice by showing that there is a reasonable probability that, but for counsel’s errors, the appellant would not have pleaded guilty and would have insisted on going to trial.

译文：

就主张律师协助无效而言，上诉人有责任证明：(a)辩护律师能力不足，以及(b)这种能力不足具有损害性；适用于涉及认罪的案件；但是，经修改，损害调查重点关注的是无效履行职责是否对答辩程序的结果产生了影响；也就是说，上诉人必须证明，如果律师未出错，上诉人合理可能不会认罪并坚持开庭审理，从而证实存在损害。

例句2：

原文：

An appellate court must indulge a strong presumption that a defense counsel’s conduct falls within the wide range of reasonable professional assistance; that is, an accused must overcome the presumption that, under the circumstances, the challenged action might be considered sound trial strategy; there are countless ways to provide effective assistance in any given case; even the best criminal defense attorneys would not defend a particular client in the same way.

译文：

上诉法院必须作出强有力的推定，即辩护律师的行为属于广泛的合理专业协助范围；也就是说，被告必须推翻这样的假设：在这种情况下，受到质疑的行动可能被视为合理的审判策略；在任何特定情况下，有无数种方法能够提供有效协助；即使是最好的刑事辩护律师，也不会以同样的方式为特定的委托人辩护。

来源：

Cornell Law School；

https://www.armfor.uscourts.gov/digest/IIA9.htm